Solid free-form fabrication (SFF) techniques are known which can be used to manufacture complex objects from a variety of materials. These objects can be used as articles of manufacture themselves, or they can be used as molds to create molded articles. The SFF methods can be adapted for use with a variety of polymeric, inorganic and composite materials to create mold structures with defined compositions, strengths, and densities, using computer aided design (CAD).
SFF techniques include stereo-lithography (SLA), selective laser sintering (SLS), ballistic particle manufacturing (BPM), fusion deposition modeling (FDM), and three dimensional printing (3DP). The present invention can be practiced with any of these SFF techniques. A preferred way of practicing the invention is with the use of three dimensional printing for fabricating the molds of the invention. 3DP is used to create molds which can be used for molding products which comprise tissue from human or other animal sources. SFF techniques can be used to form molds which have at lease one porous portion on the interior surface of the molds, where these porous portions are in communication with the exterior of the molds. According to the teachings of the invention, tissue materials can be molded into a broad variety of shapes by introducing a mixture containing tissue material into the interior of a mold according to the teachings of the invention with the tissue material mixed with one or more fluid tissue matrix components. The fluid tissue matrix component or components can be withdrawn from the tissue material through the porous portion of the mold, to the exterior of the mold. A molded tissue product is thereby produced which can be then released from the mold. Optionally, one or more additives may be included in the pore space of the mold of the invention before carrying out molding of a tissue product, and the additive if used can be removed during the molding process by withdrawing the additive through the porous structure of the mold to the mold exterior.
The macrostructure and porosity of the mold can be manipulated by controlling printing parameters, the type of polymer and particle size, as well as the solvent and/or binder. Porosity of the matrix walls, as well as the matrix per se, can be manipulated using SFF methods, especially 3DP.